Contamination control, including particulate monitoring, plays a role in the manufacturing processes of several industries. These industries require clean rooms or clean zones with active air filtration and require the supply of clean raw materials such as process gases, de-ionized water, chemicals, and substrates. In the pharmaceutical industry, the Food and Drug Administration requires particulate monitoring because of the correlation between detected particles in an aseptic environment and viable particles that contaminate the product produced.
Recent attention has been given to the monitoring and detection of biological agents. If aerosolized agents (biological particles) are introduced into an environment and are within the respirable range of particle sizes, then the biological particles may deposit in human lungs resulting in illness or death.
Biological contamination can occur not only in open air, but also in confined spaces, such as postal handling equipment, aircraft, hospitals, water supplies, and air ducts. Minimizing the introduction of biological particles in an environment requires the fast detection of pathogens. Laser-induced fluorescence (“LIF”) of fluorescent biological substances (biofluorophores) provides a real-time technique for identifying the potential presence of airborne pathogens such as aerosolized bacterial spores and viruses. Biofluorophores significant to LIF include, but are not limited to, tryptophan, NADH, and riboflavin or other flavinoids.
Assemblies that have been used in the detection of particles include pre-filter scalpers, concentrators and LIF sensors. The scalper and concentrator may be used to separate out undesirable particles and supply the air stream sample to an LIF sensor in a manner conducive to LIF detection. A scalper in this context may be a device used to separate out particles in the sample air stream, for example, based on particle size. A scalper may be used to remove large particles from the sample air stream. A concentrator may be used to increase particle concentration by increasing the number of particles by volume in the sample air stream.
Traditional implementations of LIF sensor systems use a separate scalper and a separate concentrator to prepare the sample air stream and provide particles to the LIF sensor. The separate scalper, concentrator and sensor assemblies were often bulky, which can be a disadvantage. For example, the allowable space for the detection system may be limited when the sample air stream is in an environment such as air ducts. Furthermore, tubing is required to interconnect the scalper and the concentrator with the LIF sensor. Tubing has a tendency to trap particles of interest, which frequently results in fewer particles entering the sensor.
Furthermore, in traditional LIF sensors, the sample sensor compartment where the sample stream and the incident excitation beam meet is often difficult to access. Typically, the only way to clean the sample sensor compartment is by accessing it through the various module ports, resulting in poor access to the interior surfaces that require cleaning. Furthermore, to access the interior sample sensor compartment through the ports requires the removal of either the laser module, the elastic scatter device, the photodetector device or the dispersive fluorescence detector device.
Therefore, it would be an advancement in the art to address one or more of these problems. It would also be desirable to provide an apparatus that is less bulky than previous implementations.